drivers: rpmsg: remove duplicate includes

These duplicate includes have been found with scripts/checkincludes.pl but
they have been removed manually to avoid removing false positives.

Change-Id: I1383c033db080dc7c61c5e3e94dab9555f7ed071
Signed-off-by: Pravin Shedge <pravin.shedge4linux@gmail.com>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Patch-mainline: linux-arm-msm @ 06/12/2017 9:02
Signed-off-by: Chris Lew <clew@codeaurora.org>